Dial in-bound meter interface units (MIU) dial up a central computer periodically or at predetermined times to transmit certain information. Typically the MIU seizes the line, if not busy, and dials the central computer.
U.S. Pat. No. 4,847,892, discloses a MIU having both a dial inbound and remote monitoring capability. During the dial in-bound mode, the MIU calls the computer at a preset time as determined from a clock. In the remote monitoring mode, the clock connects the data set to a subsystem which standbys during a predetermined interval to detect a call from the central computer.
The prior art, however, does not disclose a call in-bound system or methodology which allows the MIU to make scheduled and unscheduled calls to the central computer, nor a system or methodology which uses a callback scheme to reduce the potential for message collisions at the host computer or overloading of the telephone system.
Utility meters are read periodically so that a customer is billed periodically for a customer's use or consumption of utility provided service, goods or materials. However, it is also necessary to perform meter reads at unscheduled times at the request of the customer or if required by the utility. For example, if an individual has sold their house, it is common practice for the water, gas and electric meters to be read just before transferring ownership in the property. Existing call in-bound systems cannot make these kinds of readings because the MIU only functions at prespecified times. Instead a utility representative would have to be dispatched to the house to read the meter.
While a system can be initially configured to minimize message collision and overloading the telephone system, it is possible that at the scheduled call-in time a call cannot be made. Busy phone lines, bad connections, a busy host computer, for example, can contribute to a failure to make the call-in at the scheduled time. Given the large numbers of meters that are typically being read, the scheme for retry call-in's should consider the effect these calls will have on the telephone system and the host computer.
Therefore, it is an object of the present invention to provide a system and methodology where the MIU can make both scheduled and unscheduled calls to the host computer.
It is another object of the present invention to provide a system and methodology which can be used with batteryless MIU's or MIU's which require the use of energy conservation techniques.
It is a further object of the present invention to provide a system and methodology where the callback scheme considers the impact of call-in's on the phone system.
It is yet another object of the present invention to provide a system and methodology where a MIU can select a phone number to dial based on the reason for calling and the success in calling in.
It is yet a further object of the present invention to provide a system and methodology where the unscheduled call process is initiated by providing a signal to the MIU.